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Setting, Storing, and Retrieving the CCD Keywords

  Since the number of parameters involved in a complete CCD reduction is quite large, most command parameters have default values. These defaults are taken from the CCD keyword structure. So, after the data have been read in and organized, you can set the CCD keywords to control the CCD reduction process. Basically, one can divide the CCD keywords is three categories:

Although the CCD commands mostly get their input parameters from the CCD keywords, most commands accept a limited number of input parameters on the command line. These parameters will supersede the corresponding keywords. However, apart from a few cases the keyword setting itself is not modified: principally, keywords can only be changed by the SET/CCD command. For handling all these keywords the CCD package in equipped with five commands: HELP/CCD, SHOW/CCD, SET/CCD, SAVE/CCD and INIT/CCD.

HELP/CCD without parameter gives an overview of all CCD commands available. With an existing CCD keyword as parameter the command will show the present values of that keyword and a short explanation of it use.

SHOW/CCD gives you the current CCD keyword contents. Given the number of keywords, to display the information the keywords are grouped and displayed according to the functionality:

With SET/CCD up to a maximum of 8 keywords in the CCD context can be changed in one go.

After (partially) having finished a CCD reduction the user may want to store the current keyword setting. This can be done using the command SAVE/CCD. The command will store the keywords in descriptors of the CCD reduction table, or in case that isn't available, will create an empty table with descriptor information only. The keyword setting can be restored by the command INIT/CCD red_table, where red_table is the reduction table containing the CCD keyword setting, previously saved.



next up previous contents
Next: Calibration Frames and Up: CCD Reductions Previous: General Overview of



Pascal Ballester
Tue Mar 28 16:52:29 MET DST 1995